{"uid":"cap_Pssnu0XMSQUeSqFJBCrJk","slug":"agent-vending-machine-hash-attestation-67773bc6","name":"Agent Vending Machine - Hash Attestation","description":"Third-party existence attestation: submit a sha256 hash (or a payload to hash) and receive an Ed25519-signed receipt binding the hash to an issuance timestamp. Verify any receipt for free at /verify; signing public key published at /.","url":"https://agent-vending-machine.avm-7301.workers.dev/attest","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"sha256":{"type":"string","description":"Lowercase hex sha256 digest to attest (64 chars). Provide this or `payload`."},"payload":{"type":"string","description":"Raw UTF-8 payload; the service hashes it server-side. Provide this or `sha256`."}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.05","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.05/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.05","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.05","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_sk-bUJ-jGpWIOom3c6Pzk","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.05","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Submits a SHA-256 hash or raw payload and receives a signed Ed25519 receipt binding the hash to a timestamp, providing third-party existence attestation.","exampleAgentPrompt":"I need a signed existence proof for this document — please attest the SHA-256 hash a3f1c2d4e5b67890abcdef1234567890abcdef1234567890abcdef1234567890ab and give me a timestamped Ed25519-signed receipt I can use as third-party proof it existed right now.","exampleUseCases":[{"title":"Notarize contract before deadline","prompt":"I need to prove this contract existed before the submission deadline — please attest the SHA-256 hash b7e2d1f3a4c56789abcdef0987654321fedcba9876543210fedcba9876543210fe and give me a signed timestamped receipt I can show as third-party proof it was finalized before the cutoff."},{"title":"Attest dataset without revealing contents","prompt":"I want to prove I had this proprietary dataset before I shared it publicly, but without exposing the actual data — please submit this hash 9c3e5a1d2b4f6789012345678901234567890123456789012345678901234567ab to the attestation service and get me a signed Ed25519 receipt I can keep as evidence."},{"title":"Audit trail for software build","prompt":"For our compliance audit I need a tamper-proof record that this software build artifact existed at this exact moment — please attest the SHA-256 hash f1a2b3c4d5e6f7089876543210abcdef1234567890abcdef1234567890abcdef12 and return a third-party-signed timestamped receipt I can attach to the audit log."}],"resultDescription":"An Ed25519-signed receipt object binding the submitted hash (or the server-side hash of the provided payload) to an issuance timestamp, serving as cryptographic third-party proof of existence at that moment. The receipt can be independently verified for free at the /verify endpoint.","failureModes":["Invalid sha256 format (not 64 lowercase hex chars) — returns 400 error","Neither sha256 nor payload provided — returns 400 missing parameter error","Both sha256 and payload provided simultaneously — may return 400 ambiguous input error","Payment not included or insufficient USDC — returns 402 Payment Required","Service temporarily unavailable — returns 503"],"whenToPreferThis":"Use this endpoint when you need a cryptographically signed, third-party-attested timestamp receipt for a hash or payload — especially for legal, audit, or compliance purposes where you need an independent party's Ed25519 signature binding content to a moment in time. Prefer this over self-signed or chain-based solutions when you want a lightweight, verifiable receipt without blockchain overhead.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T18:33:11.357Z","isFirstParty":false}